Crosses of all shapes, sizes and colors litter the mountain, the site of a huge yearly Orthodox pilgrimage.

A statue honors the children who fought Nazis in Poland.

At first glance, this area seems like just another city park, but the lush landscape hides a dark past.

This biographical museum honors the groundbreaking scientist at her birthplace in Warsaw.

Museum dedicated to "the man who moved the Earth."

A huge wooden clock that is so beautiful its creator was forcibly blinded.

Naturally formed rock city in Poland.

A tribute to the Polish insurgents who fought in the failed attempt to end their city's Nazi occupation.

This hidden collection of everyday objects illustrates life within communist Poland.

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

This uber-quaint Polish village is known for its habit of painting elaborate floral motifs on just about everything.

A hidden art gallery in an abandoned Warsaw fort.

A fairytale Gothic castle steeped in Nazi treasure conspiracy theories.

The former Nazi concentration camp stands as a museum to remember this dark chapter in European history.

The site of the first battle of World War II.

Countless stories attempt to explain Poland's mysterious J-shaped trees.

The walls and ceiling of this Polish church are decorated with thousands of skulls, with another 21,000 skeletons just below.

A Soviet-style monument, built after transferring the remains of heroes from their graves.

While it would not look out of place among Serbian spomeniks, this massive Bulgarian monument commemorates one of their defeats.

An homage to the medieval rulers of Bulgaria.

Founded in the 4th-century, the town of Pernik plays host to the Surva Carnival⁠—a magnificent display of masked Kukeri dancers.

Rebuilt several decades ago, its striking murals prevent it from being reconsecrated as a church.

These cascading falls resonate throughout the Bulgarian forest.

This massive stone and steel monument remembers a century-old battle that cost thousands of lives and nearly destroyed the city.